Document feeding dog-ear straightening system

Abstract

An apparatus and method of straightening turned over (dog-eared) or curled edges of sheets of paper or the like, particularly, original documents being fed in a document feeder. In various sheet feeders for feeding flimsy sheets of paper or the like in a sheet feeding direction through a sheet feeding path at a desired sheet movement speed, some such sheets have or acquire folded corners which are folded back relative to said sheet feeding direction. This system can automatically unfold the leading edge sheet corners with rotatable bristled brushes. The periphery of the bristled brush extends into the sheet feeding path and is rotated at a peripheral brush bristle speed with a forward vector component in the direction of sheet movement which is substantially higher than the sheet movement speed for acquiring and lifting the folded back sheet corners and forwardly unfolding them in the sheet feeding direction while the sheet continues to move. Additional non rotating brushes can be used to remove trail edge corner dog-ears.

I claim: 
     
       1. In a sheet feeding apparatus for feeding flimsy sheets of paper in a sheet feeding direction through a sheet feeding path at a desired sheet movement speed, wherein some such sheets have acquired folded over lead edge area corners which are folded back relative to said sheet feeding direction; the improvement comprising means for automatically unfolding said folded over sheet lead edge area corners while said sheets continue to move in said sheet feeding direction, comprising rotatable brush means with rotatable peripheral brush bristles thereof operatively extending into said sheet feeding path for engaging the sheets moving therein and with means for rotating said peripheral brush bristles at a peripheral brush bristle speed having a forward vector component in said sheet feedign direction which is substantially higher than said sheet movement speed for acquiring and lifting said folded back sheet corners and forwardly unfolding said folded back sheet corners in said sheet feeding direction while the sheet continues to move in said sheet feeding direction. 
     
     
       2. The sheet feeding apparatus of claim 1, further comprising additional means for automatically unfolding folded over sheet corners which are at the trailing edge of the sheet and are folded forward relative to said sheet feeding direction, while the sheet is moving in said sheet feeding path. 
     
     
       3. The sheet feeding apparatus of claim 1, further comprising stationary brush means which are extended into said sheet feeding path for automatically unfolding folded over sheet corners which are at the trailing edge of a sheet in said sheet feeding path. 
     
     
       4. The sheet feeding apparatus of claim 1, wherein said rotatable brush means are rotated about an axis of rotation at an angle to said sheet feeding path and said sheet feeding direction. 
     
     
       5. The sheet feeding apparatus of claim 1, wherein said rotatable brush means consists of two rotatable brushes, respectively located on opposite sides of said sheet feeding path to engage opposite corners of a sheet moving in said sheet feeding path. 
     
     
       6. The sheet feeding apparatus of claim 4, wherein said angle is approximately 45 degrees. 
     
     
       7. The sheet feeding apparatus of claim 2, wherein said additional means for automatically unfolding folded over sheet corners which are at the trailing edge of a sheet moving in said sheet feeding path and are folded forward relative to said sheet feeding direction comprises a non rotating brush operatively stationarily extended into said sheet feeding path to catch said trailing edge folded forward sheet corners as they move past said brush and rearwardly unfold those sheet corners. 
     
     
       8. The sheet feeding apparatus of claim 5, wherein said two rotatable brushes are rotatably driven about axes of rotation oppositely angled outwardly of the sheet path such that the relative velocity vector between said peripheral brush bristles and the moving sheet is approximately 45 degrees for each. 
     
     
       9. The sheet feeding apparatus of claim 5, wherein one of said two rotatable brushes is substantially axially longer than the other to engage different sizes of sheets in said sheet feeding path. 
     
     
       10. The sheet feeding apparatus of claim 5, further including means for ironing out said unfolded sheet corners with a pressure nip engaging said sheet in said sheet feeding path downstream from said rotatable brushes. 
     
     
       11. A method of automatically unfolding folded over corners of a sheet, comprising the steps of: normally moving said sheet in a sheet feeding direction through a sheet feeding path at a normal sheet movement speed,   engaging lead edge area corners of said sheets which are folded back relative to said sheet feeding direction with rotating brush bristles extending into said sheet feeding path while said sheet continues to move at said normal sheet movement speed,   rotating said rotating brush bristles engaging said lead edge area corners of said sheets at a peripheral speed having a forward vector velocity component in said sheet feeding direction which is substantially higher than said normal sheet movement speed,   and acquiring, lifting, and unfolding said folded back sheet corners forwardly, in said sheet feeding direction, with said rotating brush bristles while said sheet continues to move in said sheet feeding direction.   
     
     
       12. The method of automatically unfolding folded over corners of a sheet of claim 11 further including a subsequent step of ironing out said unfolded sheet corners with a pressure nip engaging said sheet in said sheet feeding path downstream from said rotating brush bristles. 
     
     
       13. The method of automatically unfolding folded over corners of a sheet of claim 11 further including a coordinated step of automatically unfolding folded over sheet corners which are at the trailing edge of the sheet and are folded forward relative to said sheet feeding direction, while the sheet is moving in said sheet feeding path, by catching said trailing edge folded forward sheet corners as they move past a catching member and rearwardly unfolding those sheet corners. 
     
     
       14. The method of automatically unfolding folded over corners of a sheet of claim 11, wherein said rotating brush bristles are rotated about an axis of rotation at an angle to said sheet feeding path and said sheet feeding direction. 
     
     
       15. The method of automatically unfolding folded over corners of a sheet of claim 14, wherein said angle is approximately 45 degrees. 
     
     
       16. The method of automatically unfolding folded over corners of a sheet of claim 14, wherein said rotating brush bristles are provided by two rotating brushes, respectively located on opposite side of said sheet feeding path to engage opposite corners of a sheet moving in said sheet feeding path. 
     
     
       17. The method of automatically unfolding folded over corners of a sheet of claim 14, wherein said rotating brush bristles are provided by two rotating brushes, respectively located on opposite sides of said sheet feeding path to engage opposite corners of a sheet moving in said sheet feeding path, and rotatably driven about axes of rotation oppositely angled outwardly of the sheet path such that the relative velocity vector between said peripheral brush bristles and the moving sheet is approximately 45 degrees for each. 
     
     
       18. The method of automatically unfolding folded over corners of a sheet of claim 17, wherein one of said two rotatable brushes is extended substantially axially longer than the other transversely of said sheet feeding paths to engage different sizes of sheets in said sheet feeding path.